An automated method and apparatus for making sealant containing twist-on wire connectors from basic components is shown in U.S. Pat. No. 5,771,578. The apparatus through use of numerous sensors addresses one of the difficulties in making twist-on wire connectors, which is to ensure that the sealant containing twist-on wire connectors are properly assembled. Typically, the components such as the shell and coil need to be assembled before a sealant can be injected into the coil. Occasionally, the coil or the sealant may not be properly assembled or the coil or the shell may not have been properly formed. In either case the result can be a faulty product. In order to minimize faulty products the U.S. Pat. No. 5,771,578 discloses an automated system that uses a number of optical sensors to detect the presence of components for assembly. A first sensor detects if the shells are being properly fed into the peripheral slots of a rotating table. A second sensor detects if the coils are being properly fed to a rotating assembly table. A third sensor determines if the coil is properly positioned in the shell and a fourth optical sensors determines if the caps are in position. Further optical sensors are used to determine if the coil is properly positioned in the shell. If the optical sensors detect that one or more of the twist-on wire connector components is not present on the assembly table or if the twist-on wire connector does not contain the proper amount of sealant the twist-on wire connector is rejected and is sent to a recycle bin.
One of the difficulties in the use of optical sensors in the manufacture of twist-on wire connectors containing a sealant is that the optical sensor may not work properly if the color of a twist-on wire connector changes. Other times surface reflection may confuse the optical sensor. Consequently, the systems with optical sensors may have unnecessary rejects. The present method minimizes the number of unnecessary rejects.